In some situations, it is necessary to close off a tubular structure, for example in order to prevent further flow of a fluid through the structure. This may be desirable during a surgical operation, for example, where a blood vessel or other tubular structure needs to be temporarily or permanently closed off. A clip or clamp device may be used for this purpose.
Many situations require the closure of the tubular structure to be temporary, in which case, for blood vessels, it can be important to allow blood to again flow normally through the vessel once it is allowed to re-open. It can also be advantageous to avoid damage to the blood vessel during its closure, for example due to excessive compression, roughness or piercing.
One prior technique relates to a method for laparoscopic anastomosis (RU 2241391, published 12 Dec. 2004), in which a chilled sterile clip is set within the lumen of the conveyor by opening the clip jaws into a V-shape and fixing them with their rear projections. The clip is delivered and placed into the prepared holes by loosening it with the conveyor's traction with the pusher's support. When heated the clip closes its jaws and compresses the walls of hollow organs. A disadvantage of this method is its limited functionality i.e. failure to recover the blood flow in the tubular hollow elastic organ (the “vessel”).
Another technique relates to a method of clipping elastic tubular structures (RU 2213529, published 10 Oct. 2003). This method is executed via the compression of an organ by a clip made of a biologically inert alloy with a one-sided and reversible shape memory effect. Before applying, the clip is deformed at a temperature below the implantation temperature to give it an easy to install shape. The tissue is stitched with the pointed end of the clip; the clip is positioned at an application site to close the lumen (cavity) of the vessel. The clip is removed at a temperature below the implantation temperature as the clip partially opens.
A disadvantage of this method is the limited time left for manipulation and installation of the clips, as the clip's jaws are closed when reaching the temperature of the clip, which is close to the body temperature. Additionally, piercing of the tissue with a pointed end of the clip is required for secure fixation of the clip, which is unacceptable for operations on thin vessels. Also this method implies that a fairly significant cooling of body tissues, where the clip is applied, is required to remove the clip, which can either have serious consequences or can be difficult to implement.
Another technique involves a clip for anastomosis of hollow organs (RU 2285468, published 20 Oct. 2006). The clip contains a double-coil long wire. The spiral is clamped along its entire length to ensure compressive interaction and has loose wire ends at one end of the spiral, which is made from a nickel-titanium alloy (NiTi) with shape-memory effects and super elasticity. Both wires of each coil of the spiral at mostly the second end of the spiral are straightened and closed together to reach mutual contact and form the linear wires. The result is the extension of the application area due to anastomosis of small hollow organs without making extensive holes, causing injury or violating their physiology.
A deficiency of these clips is the invasiveness of the anastomosis procedure as additional piercing of the tissue is needed using ligatures. Also there is no procedure for removing the clip without causing additional trauma.
Another technique involves a clip (RU 2213529, published 10 Oct. 2003) formed of biologically inert material with a single and reversible shape memory effect, which allows the clipping of vessels and tubular organs as well as fixing the tissues via stitching at the same time. The clip can later be removed if necessary, as in the case of cavity and laparoscopic procedures. The clip is comprised of a rounded or flattened jaw that is bent so that one side forms a circular or elliptical loop, and the other side forms two parallel jaws, closely adjacent to each other, of which at least one has a bent ear in the form of a ski. There are notches on the inner side of the jaws, providing a reliable self-locking mechanism of the clips on a frame.
A deficiency of these clips is their lack of secure fixation on tubular organs and the inherent risk of slipping during organ pulsation or accidental mechanical contact with surgical instruments. Other disadvantages are inherent in the complexity of procedures for their application and removal.
Another technique involves a surgical manipulator (RU 2109488, published 27 Apr. 1998), in which the working end of a manipulator moves a pair of jaws, with the ability to open and close them. A guide node is movably mounted at the opposite end of the manipulator, and is able to interact with the transmission of the fixation and implantation mechanism. The tubular frame of the manipulator is covered with an electro-insulating layer and contains a cavity for a cooling element. The manipulator provides for a thermo-element to be embedded in the frame's cavity, which works through a thermo-electric Peltier effect cooling the compression element with thermo-mechanical shape memory.
Disadvantages of the device are in the difficulties with the design: invasiveness of the device and the inability to remove the stitching elements. Peltier elements are used for maintaining the permanent low temperature of the stitching elements in order to preserve their elastic state at the time of delivery and release. Such design leads to rapid overheating of the Peltier elements and the possible premature release of the shape memory effect, before the stitching elements are reset. Another disadvantage of this device is that shape memory elements can only be used once; it is also impossible or at least impractical to adjust them once they have been applied in cases of improper application to the connecting tissues.
Another technique involves a device for applying gripping clips (RU 2362498, published Jul. 27, 2009), which contains a stem with working branches, a feeding mechanism in the form of a movable cover, a transmission with a frame and a plate on the inner surface of which are the jambs, the height of which is a multiple of the clip's length. The plate with the jambs is secured at the distal end of an additional surface of the stem with sponges. The plate is able to move relative to the stem. It is also spring-loaded on the other side into the movable cover. The movable cover is spring-loaded by the additional spring installed at the stem with sponges on the transmission's side. A fixed sleeve is installed between the springs, and a movable sleeve is installed at the distal end. Dimensions of the movable sleeve are chosen so as to ensure its interaction with the protrusions, made on the inner surface of the movable frame. Mounting surfaces in the form of grooves and jambs for the initial installation of the plates are installed at the distal end of the movable frame.
A disadvantage of this device is that the stitching elements can only be used once and can be difficult to remove without trauma. It is also not practical to use this device for clipping vessels due to increased trauma and the risk of bleeding.
Another technique involves a device for applying gripping staples (RU 2052979, published Jan. 27, 1996), which includes a frame with mounting surfaces for the staple depot, working sponges, a transmission and a feeding mechanism. The feeding mechanism is connected to the frame with guide slots and spring-loaded handles installed in those slots. The handles are attached to an enclosure placed inside the cover, which contains a supporting surface and see-through holes. A movable lid is installed at the end of the cover, on the inner surface of which are the jambs, the height of which is a multiple of the staple's length. The jambs are able to interact with the supporting surface and see-through holes. A counting mechanism for gripping staples is installed on the outer surface of the cover. The frame of the feeder mechanism is designed as a movable part of the transmission, which is equipped with terminal clamping surfaces, which are able to rotate the sponges.
A disadvantage of this device is that the stitching elements can only be used once and can be difficult to remove without trauma. It is also impractical to use this device to clip vessels due to increased trauma and the risk of bleeding.
Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.